The present invention relates to a charging control system for automobiles, which is capable of superior control of the charging of the battery thereof.
In conventional systems, the output voltage of an AC generator is generally controlled to a fixed level for charging of the battery. These systems, however, have the disadvantage that a voltage drop occurs due to the wiring resistance between the generator and the battery, especially when the load current is increased by the operation of an electrical load, with the result that the voltage applied to the battery terminals is reduced below a predetermined value, thus often leading to the shortage of charge.
According to a conventional method of ovbiating this shortcoming, as disclosed in Japanese Patent Publication No. 55-13503, the upward trend of the load current is detected from peak value or ripple variation of the voltage at the neutral point of the generator, so that when the average value of this variation increases beyond a predetermined value, the regulation voltage is increased to compensate for the drop of the battery voltage caused by the increase of the load current.
In this case, however, the regulation voltage is changed only between two fixed high and low levels and yet is controlled in accordance with the average value of the voltage variation, thereby failing to compensate fully for the voltage drop across the battery.